Multiculturalism sounds like a good idea, right? Until you begin allowing an ideology that insists it is the only valid world view, an ideology with the stated goal of destroying or subjugating all other religions. That is what Islam intends, what it is deeply committed to.
It’s like wanting to have one big room where all the animals live together. Sounds really sweet until you put a lion in with the sheep, goats, deer and puppies. Your little zoo will become a very bloody lion’s room. Only the lion will be left and you’re a fool if you did not see it coming.
All “religions” are not the same. If you don’t protect the freedom and privileges you value, they can and will be destroyed.